The efficiency of light-emitting diodes (LEDs) has greatly increased owing to the development of semiconductor technology. Thus, LEDs have several advantages including a longer lifespan, reduced energy consumption, higher economical efficiency, and greater environmental friendliness, compared to a conventional lighting apparatus such as incandescent lamps or fluorescent lamps. Due to these advantages, currently, LEDs are in the spotlight as a light source capable of serving as a substitute therefor in traffic lights, backlights of flat-panel displays such as liquid crystal displays (LCDs), and the like.
Generally, when an LED is used as a lighting apparatus, a light-emitting module is comprised of a plurality of LEDs connected in series or parallel with one another, and control elements for controlling the turn-on and turn-off operation of the LEDs.
A conventional light-emitting module separately provides a channel for a red LED, in addition to a white LED, in order to realize a high color rendering index (CRI). Any one LED driving device included in the conventional light-emitting module is disclosed in U.S. Pat. No. 6,989,807. However, in the case of the disclosed LED driving device, the output of light from the red LED is reduced as the temperature increases, which may make it impossible to provide a high CRI.